sip41109 Vishay, sip41109 Datasheet - Page 5

• Manufacturer Part Number: sip41109
• Description: Sip41109 - Half-bridge N-channel Mosfet Driver For Dc/dc Conversion
• Manufacturer: Vishay

DETAILED OPERATION
PWM/Tri-State Enable
The PWM pin controls the switching of the external MOSFETs.
The driver logic operates in a noninverting configuration. The
PWM input stage should be driven by a signal with fast
transition times, like those provided by a PWM controller or
logic gate, (<200 ns). The PWM input functions as a logic input
and is not intended for applications where a slow changing
input voltage is used to generate a switching output when the
input switching threshold voltage is reached.
Shutdown
The SiP41109/41110 enters shutdown mode when the signal
driving PWM enters the tri-state window for more than 240 ns.
The shutdown state is removed when the PWM signal moves
outside the tri-state window. If the PWM is left open, the pin is
held to 2.5 V by an internal voltage divider, thus forcing the
tri-state condition.
Low-Side Driver
In the SiP41109, the low-side driver voltage is supplied by V
In the SiP41110, the low-side driver voltage is supplied by
PV
High-Side Driver
The high-side driver is isolated from the substrate to create a
floating high-side driver so that an n-channel MOSFET can be
Document Number: 73023
S-51104—Rev. A, 13-Jun-05
FUNCTIONAL BLOCK DIAGRAM
CC
. During shutdown, LGATE is held low.
GND
PWM
V
CC
Regulator
Linear
+5 V
Tri-State
Detect
UVLO
OTP
+8-V Linear
Regulator
New Product
CC
.
Figure 1.
SiP41109 − V
SiP41110 − V
PV
CC
used for the high-side switch. The high-side driver voltage is
supplied by PV
bootstrap capacitor, which is continually recharged by the
switching action of the output. During shutdown UGATE is
held low.
Gate Drive Voltage (PV
An integrated 80-mA, 8-V regulator supplies voltage to the
PV
output is shorted to ground. A capacitor (1 mF minimum) must
be connected to the PV
The voltage on PV
diode. PV
powers the SiP41110 low-side driver.
externally connected to V
increase high-side gate drive to 12 V. If the PV
connected to V
Bootstrap Circuit
The internal bootstrap diode and an external bootstrap
capacitor supply voltage to the BOOT pin. An integrated
bootstrap diode replaces the external diode normally needed
for the bootstrap circuit; only a capacitor is necessary to
complete the bootstrap circuit. The bootstrap capacitor is
sized according to,
CC
DRL
DRL
pin and it current limits at 200 mA typical when the
= PV
= V
CC
CC
CC
is used to recharge the bootstrap capacitor and
C
(12 V)
CC
BOOT
CC
(8 V)
. The voltage is maintained by a floating
the system voltage should not exceed 43V.
CC
= (Q
is supplied to the integrated bootstrap
CC
+
−
CC
GATE
CC
pin to stabilize the regulator output.
) Regulator
to bypass the 8-V regulator and
/(DV
V
V
(2.5 V)
DRL
BBM
SiP41109/41110
BOOT
Vishay Siliconix
UVLO
− V
PHASE
PV
CC
)) x 10
BOOT
UGATE
LGATE
www.vishay.com
PHASE
pin can be
CC
pin is
5